<template>
  <div class="app-container">
    <h2 style="text-align: center">发布新课程</h2>

    <el-steps
      :active="1"
      process-status="wait"
      align-center
      style="margin-bottom: 40px"
    >
      <el-step title="填写课程基本信息" />
      <el-step title="创建课程大纲" />
      <el-step title="提交审核" />
    </el-steps>

    <el-form label-width="120px">
      <el-form-item label="课程标题">
        <el-input
          v-model="courseInfo.title"
          placeholder=" 示例：机器学习项目课：从基础到搭建项目视频课程。专业名称注意大小写"
        />
      </el-form-item>

      <!-- 所属分类：级联下拉列表 -->
      <!-- 一级分类 -->
      <el-form-item label="课程类别">
        <el-select
          v-model="courseInfo.subjectParentId"
          placeholder="一级分类"
          @change="subjectLevelOneChanged"
        >
          <el-option
            v-for="subject in subjectNestedList"
            :key="subject.id"
            :label="subject.title"
            :value="subject.id"
          />
        </el-select>
        <!-- 二级分类 -->
        <el-select v-model="courseInfo.subjectId" placeholder="二级分类">
          <el-option
            v-for="subject in subSubjectList"
            :key="subject.value"
            :label="subject.title"
            :value="subject.id"
          />
        </el-select>
      </el-form-item>

      <!-- 课程讲师 -->
      <el-form-item label="课程讲师">
        <el-select v-model="courseInfo.teacherId" placeholder="请选择">
          <el-option
            v-for="teacher in teacherList"
            :key="teacher.id"
            :label="teacher.name"
            :value="teacher.id"
          />
        </el-select>
      </el-form-item>

      <!-- 总课时 -->
      <el-form-item label="总课时">
        <el-input-number
          :min="0"
          v-model="courseInfo.lessonNum"
          controls-position="right"
          placeholder="请填写课程的总课时数"
        />
      </el-form-item>

      <!-- 课程简介 -->
      <el-form-item label="课程简介">
        <el-input v-model="courseInfo.description" placeholder="课程简介" />
      </el-form-item>

      <!-- 课程封面 TODO -->
      <el-form-item label="课程封面">
        <!-- <el-upload
          class="upload-demo"
          action="BASE_API + '/eduoss/fileoss'"
          :on-preview="handlePreview"
          :on-remove="handleRemove"
          :before-remove="beforeRemove"
          multiple
          :limit="3"
          :on-exceed="handleExceed"
          :file-list="fileList"
        >
          <el-button size="small" type="primary">点击上传</el-button>
        </el-upload> -->
        <el-upload
          :show-file-list="false"
          :on-success="handleAvatarSuccess"
          :before-upload="beforeAvatarUpload"
          :action="BASE_API + '/eduoss/fileoss'"
          class="avatar-uploader"
          >点击上传封面
          <!-- 上传封面后会将图片显示出来 -->
          <img :src="courseInfo.cover" />
        </el-upload>
      </el-form-item>

      <!-- 课程价格 -->
      <el-form-item label="课程价格">
        <el-input-number
          :min="0"
          v-model="courseInfo.price"
          controls-position="right"
          placeholder="免费课程请设置为0元"
        />
        元
      </el-form-item>

      <el-form-item>
        <el-button
          :disabled="saveBtnDisabled"
          type="primary"
          @click="saveOrUpdate"
          >保存并下一步</el-button
        >
      </el-form-item>
    </el-form>
  </div>
</template>
<script>
import course from "@/api/edu/course";
import subject from "@/api/edu/subject";
export default {
  data() {
    return {
      saveBtnDisabled: false, // 保存按钮是否禁用
      courseInfo: {
        title: "",
        subjectId: "", //二级分类id
        teacherId: "",
        lessonNum: 0,
        description: "",
        subjectParentId: "", //一级分类id
        cover: "",
        price: 0,
      },
      courseId: "",
      teacherList: [],
      subjectNestedList: [], //一级分类列表
      subSubjectList: [], //二级分类列表
      BASE_API: process.env.BASE_API, // 接口API地址
    };
  },

  created() {
    // 初始化所有讲师
    this.getListTeacher();
    //数据回显
    //如果链接中有id，则拿到id值赋值给courseId
    if (this.$route.params && this.$route.params.id) {
      this.courseId = this.$route.params.id;
      //调用根据id查询的方法
      this.getInfo();
    } else {
      //初始化一级分类
      this.initSubjectList();
    }
  },

  methods: {
    //保存并下一步
    saveOrUpdate() {
      if (!this.$route.params.id) {
        this.saveCourse();
      } else {
        this.updateCourse();
      }
    },
    saveCourse() {
      course.addCourseInfo(this.courseInfo).then((response) => {
        // 返回信息，提示成功
        this.$message({
          type: "success",
          message: "添加课程信息成功!",
        });
        if (!this.$route.params.id) {
          this.$router.push({
            path: "/edu/course/chapter/" + response.data.courseId,
          });
        }
      });
    },
    updateCourse() {
      course.updateCourseInfo(this.courseInfo).then((response) => {
        // 返回信息，提示成功
        this.$message({
          type: "success",
          message: "修改课程信息成功!",
        });
        this.$router.push({
          path: "/edu/course/chapter/" + this.courseId,
        });
      });
    },
    //查询所有讲师
    getListTeacher() {
      course.getListTeacher().then((response) => {
        this.teacherList = response.data.item;
      });
    },
    //根据课程id查询课程信息
    getInfo() {
      course.getCourseInfoId(this.courseId).then((response) => {
        this.courseInfo = response.data.courseInfoList;
        //拿到一级分类和二级分类
        subject.getSubjectList().then((response) => {
          //获取所有的一级分类
          this.subjectNestedList = response.data.list;
          //遍历所有一级分类
          for (let i = 0; i < this.subjectNestedList.length; i++) {
            //拿到当前遍历到的一级分类
            var oneSubject = this.subjectNestedList[i];
            //如果当前courseInfo中的subjectParentId等于遍历到的一级分类id
            if (this.courseInfo.subjectParentId == oneSubject.id) {
              //对二级分类列表进行赋值
              this.subSubjectList = oneSubject.children;
            }
          }
        });
      });
    },
    initSubjectList() {
      subject.getSubjectList().then((response) => {
        this.subjectNestedList = response.data.list;
      });
    },
    subjectLevelOneChanged(value) {
      console.log(value);
      for (let i = 0; i < this.subjectNestedList.length; i++) {
        if (this.subjectNestedList[i].id === value) {
          this.subSubjectList = this.subjectNestedList[i].children;
          this.courseInfo.subjectId = "";
        }
      }
    },
    //照片成功上传
    handleAvatarSuccess(res, file) {
      console.log(res); // 上传响应
      console.log(URL.createObjectURL(file.raw)); // base64编码
      this.courseInfo.cover = res.data.url;
    },
    //图片加载完之后
    beforeAvatarUpload(file) {
      const isPictureFormat =
        file.type === "image/jpeg" || file.type === "image/png";
      const isLt2M = file.size / 1024 / 1024 < 2;

      if (!isPictureFormat) {
        this.$message.error("上传头像图片只能是JPG或png格式!");
      }
      if (!isLt2M) {
        this.$message.error("上传头像图片大小不能超过 2MB!");
      }
      return isPictureFormat && isLt2M;
    },
  },
};
</script>